A wiring board has a base insulating film. The base insulating film has a thickness of 20 to 100 .mu.m and is made of a heat-resistant resin which has a glass-transition temperature of 150.degree. C. or higher and which contains reinforcing fibers made of glass or aramid. The base insulating film has the following physical properties (1) to (6) when an elastic modulus at a temperature of T.degree. C. is given as D.sub.T (GPa) and a breaking strength at a temperature of T.degree. C. is given as H.sub.T (MPa). (1) A coefficient of thermal expansion in the direction of thickness thereof is 90 ppm/K or less (2) D.sub.23.gtoreq.5 (3) D.sub.150.gtoreq.2.5 (4) (D.sub.-65/D.sub.150).ltoreq.3.0 (5) H.sub.23.gtoreq.140 (6) (H.sub.-65/H.sub.150).ltoreq.2.3.